Heat sealing element and control of same

ABSTRACT

A vacuum packaging appliance for heat sealing items in a vacuum packaging plastic bag is disclosed. The appliance comprises a lid adapted to define a vacuum chamber when it is moved to a closed position relative to a trough in the base of the device. Adjacent to a trough in the lower portion of the device, a heat sealing element is placed in order to seal the contents of the bag once the vacuum packaging is complete. In another embodiment, the heat sealing element is mounted on the lid of the device and comes into contact with the vacuum bag when the lid is in a closed position. The heat sealing elements are controlled by a controller that allows operator selections of seals and sealing time adjustments based on inputs from a plurality of sensors. The controller is further able to energize one or two of the heating elements based on predetermined conditions. The methods and structures described control both heating and cooling of the heat sealing elements. The vacuum pump exhaust may also be directed below the heat sealing elements in order to cool the elements. The control and placement of the heat sealing elements allows for precise feedback and temperature control of the elements and therefore ensuring proper vacuum sealing of the containers.

This application claims priority to Albritton et al.'s provisionalpatent application 60/491,876, filed Jul. 31, 2003, entitled HEATSEALING ELEMENT AND CONTROL OF SAME, the contents of which areincorporated herein by reference.

TECHNICAL FIELD

The invention relates to a vacuum packaging appliance for packagingproducts and more particularly to heat sealing elements and a heatsealing controller used to seal an evacuated container once it has beenprocessed by the vacuum packaging appliance.

BACKGROUND OF THE INVENTION

Presently, various appliances and methods are used for the purpose ofvacuum sealing plastic bags and containers to protect perishables, suchas foodstuffs, and other products against oxidation. Conventionalcommercial appliances and some consumer appliances are generallyexpensive to manufacture, complex in construction and/or cumbersome tooperate. There are also different types of heat sealing mechanismscontained in these prior art devices that have limited success inhermetically sealing the evacuated bags.

One type of conventional vacuum sealing appliances uses a vacuum nozzlethat is inserted within a plastic bag for evacuation purposes. Althoughadaptable for low-volume home use, this type of system is cumbersome touse and normally requires a liquid separator or filter to preventliquids or powders, retained within the bag, from being drawn into avacuum pump connected to the nozzle. Further, a heat sealer employedtherein must be closely synchronized with the positioning and withdrawalof the vacuum nozzle from the bag. This greatly adds to the cost andcomplexity of the device itself

U.S. Pat. No. 3,928,938 discloses another type of vacuum sealingappliance that employs a heat sealing mechanism. In this appliance auser places a portion of a bag, containing a product to be packaged, ina first vacuum chamber and extends an open end or neck of the bag into asecond vacuum chamber. The first vacuum chamber is then evacuated toexpand the neck of the bag to isolate the chambers from each other. Thena vacuum is drawn in the second vacuum chamber to evacuate the bag.Thus, isolation of the two chambers from each other, during evacuationof the second vacuum chamber, is dependent on the physical propertiescomposing the neck of the bag and very close synchronization andcalibration of the evacuation and sealing procedures and controlstherefor. This complex process in conjunction with the heat sealingmechanism is not reliable.

These prior art appliances described above and others require the use ofspecial bags that must be purchased from the manufacturer. Due to thecost of the vacuum useable bags, it is desirable to conserve thematerial as much as possible. One problem with the above appliances isthat there is a substantial amount of wasted vacuum bag material betweenthe end of the bag and the heat seal as shown in Prior Art FIG. 12. FIG.12 shows a container 20, with heat seals 21 and 22. For example, thevacuum sealed container 20 of FIG. 12 may be approximately 10 inches inlength. The length between the end of the container 20 and each heatseal (21 and 22) is approximately an inch and a half. Therefore 3 inchesof bag material is essentially unused for a 10 inch vacuum sealed bag.Therefore prior art devices waste approximately 30% of the vacuum bagmaterial per use.

Another problem with prior art vacuum packaging appliances is that thetemperature of the heat sealing mechanism is not accurately controlled.This is because the prior art appliances use a simple on/off time switchto excite the heat sealing elements. Under the heat seal controlmechanism of the prior art, sealing multiple bags without allowing theheat sealing element to cool results in bags beginning to seal beforethe vacuum process is complete. This causes ineffective seals andprevents complete evacuation of gas from the bags, that results inexpensive packaging bag waste. Further, activating the elements withoutconsidering real-time temperature may cause damage to the appliance dueto element overheating.

Therefore there exists a need for a vacuum packaging appliance thataccurately controls the temperature of the heat sealing elements andoptimizes the placement of the heat sealing elements within theappliance.

SUMMARY OF THE INVENTION

The present invention sets forth several embodiments relating to theposition and control of heat sealing elements within a vacuum packagingappliance. The appliance comprises a lid adapted to define a vacuumchamber when it is moved to a closed position relative to a trough inthe base of the device. A heat sealing element is mounted in closeproximity to the trough. In another embodiment, the heat sealing elementis mounted on the lid of the device and comes into contact with thevacuum bag when the lid is in a closed position. The placement of theheat sealing element adjacent to the trough minimizes wasted bagmaterial as the heat seal is placed closer to the end of the bag itself.

In addition to the positioning of the heat sealing elements, the presentinvention also includes the controlling of these heat sealing elements.These embodiments provide features such as a heat sealing controllerthat allows an operator to select a type of heat seal formed on theevacuated container. The heat sealing controller controls the electricalcurrent supplied to the heat sealing element as selected using a controlpanel that allows the operator to select between 3 types of heat seals.The control panel is operatively connected to the heat sealing elementcontroller. The heat sealing element controller may also suspend heatsealing operations for a predetermined period of time in order to avoidheat seal element overheating. The controller also can adjust theduration of control signals applied to the heat sealing elements basedon parameters such as the real-time temperature of the elements and theamount of liquid sensed in the trough while evacuating the container.

The present invention includes a method for controlling a vacuumpackaging appliance that comprises the acts of coupling a vacuumpackaging receptacle to a vacuum circuit, hermetically separating saidvacuum circuit from ambient, operating a vacuum pump to obtain a desiredvacuum within said vacuum packaging receptacle, sensing an input relatedto the control of a heat sealing element, determining an actuationcontrol signal for energizing the heat sealing element as a function ofthe input, and then applying an actuation control signal to the heatsealing element.

In the embodiments disclosed, the input used to control the heat sealingelement may be any one or a combination of inputs such as temperature,type of heat seal selected by an operator, and amount of liquid sensedin a trough. In another embodiment, the heat seal element controller mayincrease or decrease the current provided to the heat sealing elementsto maintain a constant element temperature or maintain the elementwithin a predetermined temperature range. This type of feedback controlallows for precise temperature control. In still another embodiment, thecontroller may send a signal to direct the vacuum pump exhaust under theheat sealing elements in order to cool the elements if the sealingelements have exceeded a predetermined temperature.

In still further embodiments, the heat sealing element provided iscomprised of two sealing wires. In order to more accurately control thetemperature of the heat sealing elements and operations, one or bothwires may be activated. For example when liquids are present a heavyseal is desired so both wires are activated. If the temperature of theelements is already hot, only one wire may be activated for sealingpurposes. The heat sealing controller performs the controlling of theelements.

The present invention therefore optimizes the placement and temperaturecontrol of the heat sealing elements within a vacuum packagingappliance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of one embodiment of the vacuum packagingapparatus of the invention with the lid in a closed position.

FIG. 2 is an isometric view of the underside of the apparatus shown inFIG. 1.

FIG. 3 is an expanded isometric view of the control panel of theapparatus shown in FIG. 1.

FIG. 4 is an isometric view of the apparatus shown in FIG. 1 with thelid in an open position.

FIG. 5 is an isometric view of the apparatus shown in FIG. 1 with thelid in an open position and with the trough removed from the apparatus.

FIG. 6 is an isometric view of the trough removed from the apparatus.

FIG. 7 is transverse cross-sectional view of the device shown in FIG. 1.

FIG. 8 is another embodiment of a transverse cross-sectional view of thedevice shown in FIG. 1.

FIG. 8A is another embodiment of the heat sealing element wires.

FIG. 9 is schematic diagram of the control circuitry of the heat sealingelement.

FIG. 10 is a flowchart showing method steps of the present invention.

FIG. 11 shows a vacuum sealed bag in accordance with the presentinvention.

FIG. 12 shows a Prior Art vacuum sealed bag.

FIG. 13 is a flowchart showing method steps of the present invention.

FIG. 14 is a flowchart showing method steps of the present invention.

FIG. 15 is a flowchart showing method steps of the present invention.

FIG. 16 is a flowchart showing method steps of the present invention.

FIG. 17 is a flowchart showing method steps of the present invention.

FIG. 18 is a flowchart showing method steps of the present invention.

FIG. 19 is a flowchart showing method steps of the present invention.

FIG. 20 is a flowchart showing method steps of the present invention.

DETAILED DESCRIPTION

The present invention sets forth several embodiments relating to theposition and control of heat sealing elements within a vacuum packagingappliance. The heat sealing element may be mounted on the lid or thebase of the appliance. The placement of the heat sealing element withinthe appliance minimizes wasted bag material, as the heat seal is placedcloser to the end of the bag itself The present invention also includesa heat sealing controller that may adjust the amount of current appliedto the heat sealing element based on a number of different inputs. Itwill be understood by those skilled in the art that the description ofthe methods and structures of the vacuum packaging appliance describedbelow is not intended to be limiting in anyway.

FIG. 1 shows a vacuum packaging appliance 100 for vacuum packagingarticles in a container. The vacuum packaging appliance 100 has a lid102 and a base 104 that are pivotally connected at a back side 106 ofthe appliance 100. The lid includes a blade handle 108 that isassociated with a blade (not shown) that is slideably engaged within aslot 110 that extends substantially the entire length of the vacuumpackaging appliance 100. The blade is for cutting sections of flexiblevacuum bag material that may be stored inside the appliance 100.

FIG. 1 also shows that the base 104 of the vacuum packaging appliance100 includes an aperture 112 that is covered by a door 114. The door 114is slideably mounted in the interior of the base 104 and includes aprotrusion 116 that allows a used to more easily slide the door 114between an open and closed position. A trough for collecting debris maybe placed into the appliance 100 through this door 114. A control panel118 is coupled with the base 104 and extends above the lid 102. As willbe described with reference to FIGS. 3 and 9, the control panel 118provides and allows operator input to control the heat sealing processof the vacuum packaging appliance 100.

FIG. 2 is an isometric view of the underside of the vacuum packagingappliance 100. The vacuum packaging appliance 100 includes analternating current (AC) power cord 202 that is coupled with the base104. The base 104 also has a recess 204 for storage of the power cord202. To at least partially retain the power cord in the recess 204, thebase also includes cord retention flanges 206. In the embodiment shownin FIG. 2, the power cord 202 will supply electrical power to theheating elements and the vacuum pump of the vacuum packaging appliance100.

FIG. 3 is a magnified view of the control panel shown in FIG. 1. Thecontrol panel 118 has a face plate 302 that is removably coupled withthe base 104. The control panel 118 has a rotary dial 304, a cancelcontrol button 306, an instant seal button 308, an extended vacuumcontrol button 310, an accessory port 312 and an indicator light 314. Inalternate embodiments, various other controls maybe included in thecontrol panel 118 and/or various controls maybe excluded from thecontrol panel 118.

The rotary dial 304 has multiple positions that can control variousaspects of the vacuum packaging appliance 100, for example: “Accessory”,1, 2, 3 and “Seal Only”. However in other embodiments, the rotary dialmay have more or fewer settings that can control various aspects of thevacuum packaging appliance 100. When the rotary dial 304 is in theaccessory position, the accessory port 312 is activated and accessories(not shown) can be attached to the vacuum packaging appliance 100 eitherdirectly or via a vacuum hose. When the rotary dial 304 is in anyposition other than the accessory position, the accessory port 312 issealed off and a vacuum is not drawn through the accessory port 312.

Positions 1, 2 and 3 of the rotary dial 304 allow the user to controlthe duration of the evacuation process and the length of time the heatsealing element is activated. Position 1 may activate the sealingmechanism for a first predetermined period producing a light seal.Position 2 may activate the sealing mechanism for a second predeterminedperiod producing a medium heat seal, and position 3 may activate thesealing mechanism for a third predetermined period resulting in a heavyheat seal. Position 1 would correspond to a fragile content mode,wherein an actuation control signal would have a sealing time periodshorter than a normal content mode sealing time period. Thus, the usercan select the duration of the sealing process. For example sealingpotato chips or fruit may require a fragile or light seal; whereassealing meat would require a heavy seal. The seal only position allows auser to use the apparatus to operate a sealing mechanism only, withoutrequiring evacuation of a primary evacuation chamber.

Although the apparatus shown in FIG. 3 includes a rotary dial 304 withfive positions, in alternate embodiments the apparatus can include arotary dial 304 that has more or fewer positions. For example a “smartseal” setting may be included. When the “smart seal” is selected theappliance automatically controls the current to the heat sealingelements in accordance with the actual element temperature. Afterrepetitive uses the heat sealing elements may become hot; therefore itrequires less electrical power to heat the sealing elements to a sealingtemperature. The control of the heat sealing elements is described belowwith reference to FIG. 9.

The cancel button 306 allows a user to cancel a vacuum operation orsealing operation at any time during the operation. The instant sealbutton 308 allows a user to terminate the evacuation process and beginthe sealing process at any time during operation of the vacuum packagingappliance 100. The extended vacuum button 310 allows a user to extendthe length of time for which the container (not shown) is evacuated. Theaccessory port 312 allows a user to connect the apparatus to variouscontainers as described in U.S. Pat. 4,491,310, by Hanns J. Kristen,issued Jul. 17, 1990, and assigned to the same assignee as this patentapplication, the complete contents of which is incorporated herein byreference.

The indicator light 314 serves to notify a user of the status of thevacuum packaging appliance 100. In the embodiment shown in FIG. 3, theindicator light is off when the device is inactive, solid green whilethe device is actively evacuating a container and emits intermittentgreen flashes when the device is sealing a container. However, inalternate embodiment the light may emit light of various colors and/orintensities and/or at various intervals to indicate various operationsthat the machine is performing. For example, the indicator light 314 mayflash amber or some other color to indicate that the device is currentlydrawing an extended vacuum or the indicator light 314 may glow red toindicate that the accessory port 312 is active. In still furtheralternate embodiments, the control panel 118 may not include anindicator light 314.

FIG. 4 is an isometric view of the apparatus 100 shown in FIG. 1 withthe lid 102 in an open position. The lid 102 includes a primaryevacuation chamber 408 that is surrounded by a flexible gasket 406. Theprimary evacuation chamber 408 is coupled to a vacuum source housedinside the vacuum packaging appliance 100. The lid also includes a heatsealing element 433. The heat sealing element 433 touches electricalcontacts 431 and 432 on the base of the device when the lid is closed.In this manner power is supplied to the heat sealing element via thecontacts. This is desirable, as no power cord is necessary to runthrough the device hinges into the lid 102. This reduces the complexityof the device itself In alternate embodiments, the heat sealing elementmay be 2 wires or a wider element to ensure a proper heat seal.

The base 104 of the vacuum packaging appliance 100 includes anelectromechanical switch 416, positioned on the base such that when thelid 102 is in a closed position, the protrusion 414 is substantiallyvertically aligned with the electromechanical switch 416. Thus, when thelid 102 is in a closed position and then is further depressed, theprotrusion 414 can actuate the electromechanical switch 416 and activatethe vacuum packaging appliance 100.

The base 104 of the vacuum packaging appliance 100 shown in FIG. 4 has arecess 422 that is adapted to hold container material 424. The vacuumpackaging container material 424 is a roll of flattened, tubularcontainer material and is supported on rotational supports 426. Therotation supports 426 are designed to engage the ends of the roll ofcontainer material 424 and rotate freely within the recess 422. In afurther embodiment, the roll or container material 424 may simply beplace or stored in the recess 422 without any support mechanism tofacility dispensing the container material 424.

The roll of container material may be a single roll of continuouslybonded plastic as described in U.S. Pat. No. RE34,929, by Hanns J.Kristen, issued May 9, 1995 a reissue patent based on U.S. Pat. No.4,756,422, by Hanns J. Kristen, issued Jul. 12, 1988, assigned to theassignee of the present application, the complete contents of which isincorporated herein by reference. However, in alternate embodiments, theroll of container material 424 may be any convenient material.

The thermal sealing mechanism 433 includes one or more electricallyconductive wires that produce heat when a voltage differential isapplied across the length of the wire. In the embodiment shown, theelectrically conductive wires are covered with a Teflon tape. However,in alternate embodiments, the wires maybe exposed or wrapped in amaterial. If the sealing mechanism 433 is activated and containermaterial 424 is disposed between the sealing gasket 406 and the sealingmechanism 433, the container material 424 can be hermetically sealed.Although the apparatus 100 is described as including a sealing mechanism433 that is integrated with the apparatus, in alternate embodiments, thesealing mechanism 433 may be on the base of the device while theelectrical contacts are located on the lid. Additionally in alternateembodiments, various other placements of the heat sealing mechanisms 433may be employed in order to seal the container material 424.

In operation, when the lid 102 is in a closed position and is depressedsuch that the protrusion 414 actuates the electromechanical switch 416,the vacuum pump or source is activated. Evacuation of the primaryevacuation chamber 404 and trough 430 is then performed. When the lid102 is in a closed position, the gasket 406 surrounding the primaryevacuation chamber 408 and the trough 430 are substantially verticallyaligned such that a vacuum circuit is obtained or formed.

For cleaning purposes, the trough 430 is removable from the base 104 ofthe vacuum packaging appliance 100 through the aperture 112 when thedoor 114 is in an open position. In the embodiment shown in FIG. 4 thedoor 114 is manually slideable between and open and a closed position.However, in alternate embodiments, the door can be mechanically operatedand/or can open in any convenient fashion. In still further alternateembodiments, the door 114 may not be present.

In operation, a user inserts an open end of a container, such as aflexible bag, into the trough 430 or attaches a container to theaccessory port 312. The user then selects a setting on the rotary dial304, closes the lid 102 and depresses the lid 102 past the closedposition to actuate the electromechanical switch 416 with the protrusion414. The vacuum source 434 will then evacuate the latch chambers 402 tohold the lid 102 relative to the base 104. Once the lid 102 is securedrelative to the base 104, the primary evacuation chamber 408 and thetrough 430 are evacuated thus evacuating the open container insertedinto the appliance 100. When the vacuum strength reaches a predeterminedlevel, the sealing mechanism 433 will be activated to seal thecontainer. The evacuated and sealed container may then be released fromthe vacuum packaging appliance 100.

FIG. 5 is an isometric view of the apparatus shown in FIG. 4 with thetrough 430 removed and the door 114 in an open position. The embodimentshows a recess 502 in which the trough 430 may be inserted and removed.The recess 502 has retention flanges 504 that are designed to preventsubstantial vertical and rotational movement of the trough 430 withinthe recess 502. The recess 502 has a slot 506 at the end of the recess502 opposite the door 114. The slot 506 is designed to mate with aprotrusion in the trough 430 in a snap-fit manner. The snap-fit matingof the slot 506 and the recess in the trough 430 is designed to restricthorizontal movement of the trough 430 within the recess 502.

FIG. 6 is an isometric view of the trough 430. The trough 430 includesan extension that includes a protrusion 602. The protrusion 602 isdesigned to mate with the slot 506 in a snap-fit manner. The embodimentshown in FIG. 6 includes flanges 604 that, as described with referenceto FIG. 5, are designed to engage with the retention flanges 504. Theembodiment shown in FIG. 6 also includes a handle 606. The handle isincluded to facilitate removal and insertion of the trough 430.

FIG. 7 is a sectional view of the apparatus shown in FIG. 1, cut alongthe section line A-A. FIG. 7 shows the lid 102 in a closed positionrelative to the base 104. The base 104 includes the thermal sealingmechanism 420 that is positioned in substantial vertical alignment withthe sealing gasket 406 in the lid 102 of the appliance. When the lid 102is in a closed position relative to the base 104, the gasket 406 thatsurrounds the primary evacuation chamber 408 and the trough 430 are insubstantial vertical alignment and are in contact, thus defining anevacuation chamber. The embodiment shown in FIG. 7 also shows a roll ofcontainer material 424 that is stored within the appliance 100, and avacuum pump 434.

The embodiment of FIG. 7 shows a heat sealing element 420 mountedadjacent to the trough 430. In operation, the element 420 receiveselectrical current from a power source or sources that causes theelement to heat up to temperatures exceeding 130 degrees thereby heatsealing the vacuum bag. As the location of the heat sealing element 420is behind the gasket 406, this results in a seal that is close to thebag edge which results in the minimization of bag material necessary forpackaging. Sensor 90 is a temperature sensor and is located adjacent tothe sealing elements 420. Sensor 91 is a liquid sensor that senses theamount and presence of liquid in the trough 430. Both these sensors feedsignals back to a controller as shown in FIG. 9, that supplies power viacontrol signals to the heat sealing elements 420. The present inventionis described as a piston-type vacuum, however the vacuum source 434 maybe any convenient mechanism capable of drawing a vacuum.

FIG. 8 shows a vacuum sealable container 804 being placed into theappliance. In this embodiment the front side of the trough 430 includesthe heat sealing elements 420 and an extension that includes aprotrusion 802. The protrusion 802 is designed to seal the evacuationchamber and trough with the gasket 406. This view of the appliance showsthe vacuum chamber 430 and lid 102 in an open position. A vacuumpackaging bag 804 that is designed to be heat sealed by elements 420 isplaced into the front of the appliance by the user. The gasket 406 isone continuous loop around the rectangular trough and vacuum chamber430. The front side of gasket 406 is wider than the back side of thegasket. The gasket 406 is wider on the front side as the gasket 406 isperforming multiple functions and this ensures that a proper vacuum sealis obtained.

As can be seen from FIG. 8, the gasket is used to create a seal but alsoto hold the vacuum packaging receptacle 804 in contact with the heatsealing elements 420 located adjacent to the trough 430. The presence ofthe bag 804 also requires a wider gasket 406 to ensure a proper seal.The back side of the gasket 406 does not perform multiple functions asthe front side does, therefore it may be smaller in width. The gasket406 is also only located on the lid 102 of the appliance. In thisembodiment there is no need for an additional gasket mounted around thetrough in the base of the appliance. This is another feature andadvantage of the present invention.

Also shown in FIG. 8 are valves 808 and 812 and passages 806 and 810.The valve 808 is electrically controlled (by a controller as shown inFIG. 9) and is used to open and close an opening into a passageway 806.When the valve 808 is opened, the exhaust from the vacuum pump isdirected through the passage 806. The passage runs underneath the entirelength of the heating elements 420. The exhaust moving through thepassage provides a cooling effect to reduce the temperature of theelements 420. After the exhaust has passed through the passage 806 andcooled the elements, the exhaust travels through an exit passage 810 andan exit valve 812.

The opening of the valve 808 is controlled by a signal from a heatsealing element controller that receives a temperature sensor input. Thevalve 808 is opened by the controller in response to a predeterminedtemperature of the heat sealing elements being exceeded. For example, ifthe heat-sealing layer of the vacuum packaging bag melts at 130 degrees,the predetermined temperature may be set at 120 degrees. This ensuresthat the heat sealing elements 420 stay below a melting temperature, soas to not prematurely produce a heat seal while the vacuum packaging bagis being evacuated. The controller may also open and close the valve 808as necessary, in order to keep the heat sealing elements at a constantpredetermined temperature or within some range below the predeterminedtemperature. A flowchart of the steps in this process is shown in FIG.19.

FIG. 8A shows an embodiment of the present invention wherein the vacuumpackaging appliance has two heat sealing elements. FIG. 8A shows a viewlooking at the base of the appliance 104 from above, as a vacuum bag 804is placed in to the appliance and into the trough 430. In thisembodiment the heat sealing elements are comprised of two separatewires, 441 and 442. Each wire when actuated with a current signal from acontroller, becomes hot enough to melt the sealing layer of the vacuumpackaging receptacle 804. As will be described below with reference toFIGS. 9 and 13-18, these two heat sealing element wires 441 and 442 areindividually controlled to allow for precise temperature control basedon a number of predetermined settings and/or predetermined conditions.For example, heavy seals are created by energizing both wires, whilelighter seals are produced energizing only one of the two wires 441 or442, wherein the heavy and light seals may be desired for a variety ofreasons as described below.

A schematic diagram of the control circuitry of the heat sealing elementis shown in FIG. 9. Included is the temperature sensor 90 that feeds areal-time temperature signal back to the controller 92. The controller92 is an application specific integrated circuit or (ASIC) device. Thecontroller 92 may also be a programmable logic device (PLD) or any othertype of microprocessing device capable of being programmed to controlthe functions of the vacuum packaging appliance as described herein. Asmentioned above, problems with overheating and faulty sealing resultfrom inaccurate temperature control of the heat sealing elements 420.The sensor 90 allows the controller 92 to supply more or less electricalpower to the elements based on this temperature. For example a standardheavy seal would be to supply current to the elements for 5 secondscreating a vacuum bag temperature of 130 degrees (required to melt theinterior heat sealing layer). If the present heat sealing elementtemperature is already 110 degrees, a heavy seal may be produced by onlysupplying current for a duration of 2 seconds. This process therebyincreases the power efficiency of the appliance and does not damage theheat sealing elements 420 by overheating them with a full 5 secondduration heavy seal pulse. In addition to changing the pulse duration,the controller may also change the amplitude of the pulse or change bothamplitude and duration if desired. When controlling actuation pulses tothe two elements as shown in FIG. 8A, the controller 92 may actuate onlyone of the wires 441 or 442 based on temperature conditions as describedabove. For example, if the elements are already warm, only one element441 is energized. If the elements are cool, both wires 441 and 442 areactuated by the controller 92.

The liquid sensor 91 feeds a signal back to the controller 92 indicatingthe presence or amount of liquid in the trough 430. This is important asthe presence of liquids may require higher sealing temperatures of theelements 420, as liquids tend to reduce the effects of the heat sealingelements. Therefore the controller 92 would produce a heat sealactivation signal of greater duration when liquids are present, or sendsealing actuation pulses to both sealing elements 441 and 442 as shownin FIG. 8A. FIG. 15 shows this process in detail. Regarding the detailsof the liquid sensor, patent application with Ser. No. 60/492,046,entitled “Fluid Sensing in a Drip Tray”, by inventors Charles WadeAlbritton, Landon Higer and John Peters, which is hereby incorporated byreference.

FIG. 10 shows a method of controlling the vacuum packaging device. Instep S10 the process is begun when the operator seals a first end of thecontainer bags. It may be desired to seal a first and second end of thevacuum bags in the exact same manner by the operator. Sealing both endsof the bag in the same manner ensures an ease of operation that resultsin less operator errors and thereby decreases the wasted bag material.After a first end of the bag has been sealed the operator places itemsto be packaged into the bag. The bag that is ready for sealing is thenplaced into the device for evacuating and heat sealing the second end ofthe container in step S20. In step S30 the operator selects theappropriate type of seal. In step S40 the heat sealing element may bemoved into position by closing the lid of the device itself In step S50the heat sealing controller instigates the chosen type of seal bycontrolling the current to the sealing element or elements. As describedabove, the heat sealing process is controlled by the controller 92 inaccordance with the inputs from multiple sensors and internal logic andprogramming. The process is then finished in step S60.

The sealed bag of the present invention is shown in FIG. 11. The vacuumsealed container 10 has heat seals 11 and 12 after being processed bythe vacuum packaging appliance. The length of bag material between theends and the heat seals 11 and 12 is minimized. By incorporating theheat sealing element adjacent to the trough, the seal may be placedcloser to the container end, thereby resulting in less bag waste. Thisis a substantial improvement over prior art bags as shown in FIG. 12.FIG. 12 shows heat seals 21 and 22 that are far from the bag endsresulting in substantial waste and cost to the user.

FIG. 13 shows a method 1300 of controlling the vacuum packaging device.In step S1302 the process begins when the operator couples the storagereceptacle to the vacuum circuit by placing the container into thevacuum packaging appliance. In step S1304, the vacuum circuit is closedwhen the operator closes the lid of the device. In step S1306 the typeof heat seal is determined. As is described below and as shown in FIGS.14-18, this step may contain inputs from a variety of parameters inorder to determine the exact nature of the control signal applied to theheat sealing elements. In step S1308 the container is evacuated and isready for sealing. In step S1310 the heat sealing element is actuatedaccording to the determined control signal. This step may includedetermining if one or both wires 441 and 442 (as shown in FIG. 8A) areto be actuated. In step S1312 feedback of the heat sealing process isprovided to the user. For example lights on the control panel mayindicate that sealing is being performed and/or that the heat sealingprocess is complete. As shown in FIG. 9, the heat sealing controllerdetermines and actuates the current provided to the heat sealingelement. As described above, the heat sealing process is controlled bythe controller 92 in accordance with the inputs from multiple sensorsand internal logic and programming.

FIG. 14 shows in more detail how the control signal is determined instep S1310 above. The process begins in step S1402 by receiving the userinput regarding the type of heat seal selected. This input comes fromthe control panel shown in FIG. 3 and described above. In step S1404 theproper control signal is determined by the controller 92. In this mannerthe time of the control signal to the heat sealing elements is input. Aswill be described below, the control signal set by the operator maychange in accordance with the amount of liquid sensed in the troughand/or the temperature of the heating elements.

FIG. 15 shows in more detail how the control signal may be adjusted instep S1310 above. The process begins in step S1502 by monitoring thepresence and amount of liquid in the trough during the evacuationprocess in step S1308. The liquid sensing electrodes as shown in FIG. 7provide this information to the controller circuit 92. In step S1504 itis determined by the controller if a predetermined threshold of liquidhas been exceeded. If the liquid is below a certain level, step S1508 isenacted and the time of the control signal to the heat sealing elementsis set to a normal period (as set by the operator). If it has beendetermined in step S1504 that a predetermined amount of liquid ispresent, step S1506 adjusts the set time of the control signal to theelements to be high or energizes both heat sealing wires 441 and 442 asshown in FIG. 8A. By incorporating the liquid sensing electrodes intothe trough of the appliance, the heat seal may be controlled in a moreprecise manner, thereby resulting in less bag waste. This is asubstantial improvement over prior art devices that are incapable ofmonitoring and adjusting the heat sealing process in accordance with theamount of liquid detected during the evacuation process.

FIG. 16 also shows in detail how the control signal is determined instep S1 310 above. The process begins in step S1602 by monitoring thepresent temperature of the heat sealing elements. The temperature sensoras shown in FIG. 7 provides this information to the controller circuit92. In step S1604 the controller determines if a predetermined thresholdof temperature has been exceeded. If the temperature is below a certainlevel, step S1608 is enacted and the vacuum packaging appliancecontinues with the evacuating and heat sealing operations in a normalmanner. If it has been determined in step S1604 that a predeterminedtemperature has been exceeded, step S1606 waits or suspends operationsfor a predetermined period of time until the heat sealing elements havecooled.

By incorporating the temperature sensor adjacent to the trough of theappliance, the heat seal may be controlled in a more precise manner,thereby resulting in less bag waste. This is a substantial improvementover prior art devices that are incapable of monitoring and adjustingthe heat sealing process in accordance with a plurality of sensor inputsand control modes.

In addition to suspending the heat sealing operations as describedabove, the present invention is also capable of adjusting the controlsignal times based on the temperature of the elements. FIG. 17 shows aflowchart of steps 1700 enacted by the controller 92. The controller 92stores control signal times for all the heat seal settings from whichthe operator may select. A light or heavy seal control signal timeduration may also be increased or decreased based on the real-timefeedback of the temperature of the heat sealing elements. The controller92 may therefore be programmed to keep the heat sealing elements at aconstant temperature while sealing or within a predetermined temperaturerange while sealing.

The process begins in step S1702 when the temperature of the heatsealing elements is detected and sent to the controller. In step S1704the controller adjusts the duration of the control signal applied to theheat sealing elements based on their real-time detected temperature. Asper the algorithm mentioned above, more or less current may be appliedto the elements based on their sensed temperature. For example a warmheating element may require 3 seconds of current to produce a seal,whereas a cold heat sealing element may require 5 seconds of current toproduce a similar heat seal. In addition to varying the activationsignal duration, other embodiments may adjust the amplitude and/orduration of the control signal in a real-time manner as applied to eachindividual sealing wire 441 and 442 as shown in FIG. 8A. Step S1704 mayalso include waiting for the heat sealing elements to cool down.

The algorithm enacted by controller 92 can also adjust waiting times forcooling periods. For example a wait time of 20 seconds may be requiredfor a hot element at 150 degrees to cool down to 100 degrees, and a waittime of 10 seconds may be required for an element at 135 degrees to coolto 100 degrees. It is also contemplated that the algorithm can maintainthe element temperature at some constant temperature during the sealingprocess.

FIG. 18 shows another method of the present invention. In this methodthe controller 92 adjusts the control signal provided to the elementsbased on inputs from the control panel, the temperature of the heatsealing elements, and the amount of liquid sensed in the trough. Theprocess begins in step S1802 by receiving the user selected type of heatseal. In step S1804 the controller receives information regarding thetemperature of the heat sealing elements from the temperature sensor 90.In step S1806 the controller receives information regarding the amountof liquid in the trough from the liquid sensor 91. In step S1808 thecontroller takes into account all the information described above andadjusts the control signal based on the selected seal setting, thetemperature of the elements and the amount of liquid in the trough. Theappropriate control signal is then sent from the controller to actuatethe sealing elements in step S1810.

For example, the operator may select a medium heat seal which would havea control signal duration of 4 seconds. If the temperature of the heatsealing elements was detected to be 110 degrees, 0.5 seconds of timeduration may be subtracted from the control signal, as the heat sealingelements are already warm. If a substantial amount of liquid is detectedby the liquid sensors, the controller may add 1.0 second of time to theduration of the control signal. This results in an appropriate controlsignal duration of 4.5 seconds to be applied to the heat sealingelements. The controller 92 may use an algorithm or look-up table todetermine these adjusted control signal periods based on these pertinentparameters.

In another embodiment, the process as shown in FIG. 18 is also appliedto the heat sealing wires as shown in FIG. 8A. In this environment, thecontroller 92 adjusts the control signal (in an on/off manner) providedto the plurality of elements based on inputs from the control panel, thetemperature of the heat sealing elements, and the amount of liquidsensed in the trough. For example, when the elements are detected to behot (a predetermined temperature has been exceeded) as sensed by thetemperature sensor, only one of the two wires may be energized. Whenliquids are detected, both wires 441 and 442 are activated to ensurethat the presence of liquid does not effect the heat seal. The operatormay also select a “light” or “heavy” seal by using the control panelswitches. In this instance a “light” seal would activate only one wire,while a “heavy” seal wold activate both wires.

FIG. 19 shows a flowchart of steps in another embodiment of the presentinvention. The process begins in step S1902 by monitoring the presenttemperature of the heat sealing elements as the vacuum packagingappliance is evacuating a receptacle. The temperature sensor as shown inFIG. 7 provides this information to the controller circuit 92. In stepS1904 the controller determines if a predetermined threshold oftemperature has been exceeded. If the temperature is below a certainlevel, step S1908 is enacted and the vacuum packaging appliancecontinues with the evacuating and heat sealing operations in a normalmanner.

If it has been determined in step S1904 that a predetermined temperaturehas been exceeded, step S1906 is enacted wherein the controller producesa signal that opens a valve which enables the vacuum pump exhaust to beblown under the heat sealing elements in order to cool the elements.This process provides real-time feedback and control of the heat sealingelements temperature. This process reduces the amount of faulty sealsthat occur when the elements are warm from previous use and begin toprematurely melt the heat sealing layer within the vacuum packaging bagsbefore they are completely evacuated. This process also ensures that theheat sealing elements maintain an acceptable temperature range so thatthey may be subsequently controlled by the controller using the methodsdescribed above.

FIG. 20 illustrates a preheat method according to another embodiment ofthe present invention. This method is well suited to particularly thickvacuum packaging receptacles and vacuum packaging receptacles that havelarge ridges or patterns thereon. A step S100 begins by energizing asealing mechanism to a preheat level. The preheat step S100 is typicallydone in conjunction with an evacuation step, rendering the receptacleready for easy and prompt sealing. The preheat step S100 could raise thesealing mechanism temperature to any suitable level, for examplesomewhat lower than the actual sealing temperature. This prepares thereceptacle for actual sealing, but does not initiate substantial sealingthat tends to interfere with evacuation. A step S102 completes thesealing process by fully energizing the heat sealing mechanism.

The appliances described above show the heat sealing mechanism externalto the vacuum chamber. However, the teaching of the present inventionworks equally well with appliances having the heat sealing mechanisminternal to the vacuum chamber. One suitable example of this is commonlyassigned U.S. provisional patent application 60/492,090, filed Jul. 31,2003, and incorporated herein by reference. Additionally, the appliancesdescribed illustrate the receptacle external to the vacuum chamber. Aswill be appreciated, the teachings of the present invention work wellwith in-chamber vacuum packaging appliances.

The vacuum packaging device described herein therefore provides numerousembodiments and methods to cool the heat sealing elements andembodiments and methods to control and energize the heat sealingelements that may be used in combination or separately as desired. Itwill be understood by those skilled in the art that the above-presenteddescription is provided by way of example only and is not intended to belimiting in anyway. Those skilled in the art will readily understandthat numerous other embodiments of the invention are contemplated andpossible which meet the scope and spirit of the invention.

1. A method for controlling a vacuum packaging appliance, said vacuumpackaging appliance including a heat sealing element, a vacuum circuit,and a vacuum pump, said vacuum pump operable to evacuate gas from saidvacuum circuit, said heat sealing element operable to heat seal a vacuumpackaging receptacle, said method comprising: coupling said vacuumpackaging receptacle to said vacuum circuit; hermetically separatingsaid vacuum circuit from ambient; operating said vacuum pump to obtain adesired vacuum within said vacuum packaging receptacle; sensing an inputrelated to control of said heat sealing element; determining anactuation control signal for energizing said heat sealing element as afunction of at least said input; and applying said actuation controlsignal to said heat sealing element.
 2. A method for controlling avacuum packaging appliance as recited in claim 1, wherein said vacuumpackaging receptacle is a vacuum packaging bag having three sealed sidesand one unsealed side, and said coupling includes: engaging said vacuumcircuit with said unsealed side of said vacuum packaging bag.
 3. Amethod for controlling a vacuum packaging appliance as recited in claim2, wherein said input is related to a temperature of said heat sealingelement.
 4. A method for controlling a vacuum packaging appliance asrecited in claim 1, wherein said input arises from a user activatedswitch.
 5. A method for controlling a vacuum packaging appliance asrecited in claim 3, wherein said input arises from a temperature sensor.6. A method for controlling a vacuum packaging appliance as recited inclaim 2, wherein said input corresponds to a high liquid content mode,said actuation control signal corresponding to said high liquid contentmode having a high liquid content sealing time period longer than anormal content mode sealing time period.
 7. A method for controlling avacuum packaging appliance as recited in claim 1, wherein said vacuumcircuit contains a trough for collecting liquids while operating thevacuum pump.
 8. A method for controlling a vacuum packaging appliance asrecited in claim 7, wherein said input arises from a sensor monitoring afluid level present in the trough of said vacuum circuit.
 9. A methodfor controlling a vacuum packaging appliance as recited in claim 5,wherein said heat sealing element is controlled in accordance with aplurality of inputs.
 10. A method for controlling a vacuum packagingappliance as recited in claim 9, wherein said vacuum pump operation isdelayed until said temperature of said heat sealing element cools to apredefined temperature which tends to prevent premature sealing of saidvacuum packaging receptacle.
 11. A method for controlling a vacuumpackaging appliance as recited in claim 1, wherein said input is relatedto a time period since said heat sealing element has been actuated. 12.A method for controlling a vacuum packaging appliance as recited inclaim 9, wherein a duration and amplitude of said activation controlsignal may be changed.
 13. A method for controlling a vacuum packagingappliance as recited in claim 1, further comprising providing said userfeedback related to operation of said heat sealing element.
 14. A methodfor controlling a vacuum packaging appliance as recited in claim 13,further comprising providing said user feedback related to operation ofsaid vacuum pump.
 15. A method for controlling a vacuum packagingappliance as recited in claim 14, wherein lights on a control panelprovide said user feedback relating to the operation of said heatsealing element and said vacuum pump.
 16. A vacuum packaging appliancefor evacuating a container comprising: a base defining an upper supportsurface adapted to receive an open end of a container; a lid operativelyassociated with said base, said lid and said base defining a vacuumchamber therebetween to receive said open end of said container; atleast one gasket surrounding said vacuum chamber for directly engagingsaid container such that said open end of said container is operativelyassociated with said vacuum chamber; a vacuum source operativelyassociated with said vacuum chamber for selectively evacuating saidvacuum chamber and said operatively associated container; a troughcoupled to the base for receiving the open end of a container andcollecting contents taken from the container while evacuating saidcontainer, wherein a heat sealing element is located adjacent to thetrough in order to heat seal the evacuated container; and a heat sealingcontroller that allows an operator to select a type of heat seal formedon the evacuated container.
 17. The vacuum packaging appliance of claim16 wherein said heat sealing controller controls the electrical currentsupplied to the heat sealing element.
 18. The vacuum packaging applianceof claim 16 further comprising a control panel that allows the operatorto select between 3 types of heat seals.
 19. The vacuum packagingappliance of claim 18 wherein said control panel is operativelyconnected to the heat sealing element controller.
 20. The vacuumpackaging appliance of claim 18 wherein said heat sealing elementcontroller may suspend heat sealing for a predetermined period of timein order to avoid heat seal element overheating.
 21. A method ofcontrolling a vacuum packaging appliance to evacuate and seal acontainer comprising the acts of: placing a first end of a containerinto a trough within a vacuum packaging appliance; evacuating thecontainer of gases; selecting a type of heat seal for the container;positioning a heat sealing element to heat seal the container; andcontrolling the amount of current applied to heat sealing elements basedon the selected type of seal.
 22. The method of claim 21 wherein theheat sealing elements are positioned in the trough of the vacuum sealingdevice.
 23. The method of claim 21 wherein the heat sealing element ispositioned on a lid of the vacuum sealing device.
 24. The method ofclaim 21 wherein the heat sealing element is positioned to minimize thelength of the container necessary for vacuum sealing.
 25. The method ofclaim 21 wherein controlling the amount of current to the heat sealingelement may include waiting a predetermined period of time beforesupplying current to the heat sealing element in order to avoidoverheating or premature sealing of the container.
 26. The method ofclaim 21 wherein controlling the amount of current to the heat sealingelement may include controlling the current based on the temperature ofthe heat sealing elements or the presence of liquid within the trough.27. A vacuum packaging appliance for evacuating a container comprising:a trough for receiving the open end of a container and collectingcontents taken from the container while evacuating said container, aheat sealing element located adjacent to the trough in order to heatseal the evacuated container; and a heat sealing controller that allowsan operator to select a type of heat seal formed on the evacuatedcontainer.
 28. The vacuum packaging appliance of claim 27 wherein saidheat sealing controller controls the power supplied to the heat sealingelements.
 29. The vacuum packaging appliance of claim 28 wherein aliquid sensor is connected to said heat sealing controller.
 30. Thevacuum packaging appliance of claim 29 wherein a temperature sensor isconnected to said heat sealing controller
 31. The vacuum packagingappliance of claim 29 wherein the liquid sensor is located in thetrough.
 32. A vacuum packaging appliance for use in evacuating vacuumpackaging receptacles, said vacuum packaging appliance comprising: avacuum pump; a vacuum circuit coupled to said vacuum pump such thatactuation of said vacuum pump evacuates said vacuum circuit, said vacuumcircuit intended for evacuating a vacuum packaging receptacle; a heatsealing element arranged to hermetically seal said vacuum packagingreceptacle; a user input device enabling a user to select a mode ofoperation from among at least a first and a second operating mode; and aheat sealing element controller operable to actuate said heat sealingelement according to a first control profile associated with said firstoperating mode and a second control profile associate with said secondoperating mode, said heat sealing element controller responsive to saiduser input device.
 33. A vacuum packaging appliance as recited in claim32, wherein said user input device includes a toggle switch configurableto at least a first position corresponding to said first operating modeand a second position corresponding to said second operating mode.
 34. Avacuum packaging appliance as recited in claim 32, wherein said heatsealing element controller includes a microprocessor.
 35. A vacuumpackaging appliance as recited in claim 32, wherein said heat sealingelement controller includes an application specific integrated circuit(ASIC).
 36. A vacuum packaging appliance as recited in claim 32, whereinsaid heat sealing element controller includes a programmable logicdevice (PLD).
 37. A vacuum packaging appliance for use in evacuating avacuum packaging receptacles, said vacuum packaging appliancecomprising: a vacuum pump; a vacuum circuit coupled to said vacuum pumpsuch that actuation of said vacuum pump evacuates said vacuum circuit,said vacuum circuit intended for evacuating a vacuum packagingreceptacle; a heat sealing element arranged to hermetically seal saidvacuum packaging receptacle; a sensor providing data related to saidheat sealing element; and a heat sealing element controller operable toactuate said heat sealing element according to a control profile that isa function of said data related to said heat sealing element.
 38. Avacuum packaging appliance for use in evacuating vacuum packagingreceptacles as recited in claim 37, wherein said sensor measures aparameter related to a temperature of said heat sealing element.
 39. Avacuum packaging appliance for use in evacuating vacuum packagingreceptacles as recited in claim 38, wherein said sensor measures aparameter related to a fluid level in said vacuum circuit.
 40. A vacuumpackaging appliance for use in evacuating vacuum packaging receptacles,said vacuum packaging appliance comprising: a vacuum pump; a vacuumcircuit coupled to said vacuum pump such that actuation of said vacuumpump evacuates said vacuum circuit, said vacuum circuit intended forevacuating a vacuum packaging receptacle; a heat sealing elementarranged to hermetically seal said vacuum packaging receptacle; acontrol panel to allow an operator to select a type of heat seal forsealing the vacuum packaging receptacle; a sensor providing data relatedto a temperature of the heat sealing element; a sensor providing datarelated to an amount of liquid present in the vacuum circuit whileevacuating the vacuum packaging receptacle; and a heat sealing elementcontroller operable to actuate said heat sealing element with a controlsignal; wherein the duration of the control signal is determined by thetype of heat seal selected, the temperature of the heat sealing element,and the amount of liquid present.
 41. A heat sealing device used in avacuum packaging appliance comprising: a heat sealing element forhermetically sealing a vacuum packaging container placed in the vacuumpackaging appliance; a temperature sensor for sensing the temperature ofthe heat sealing element; and a heat sealing element controller thatcontrols the temperature of the heat sealing element based on a signalfrom the temperature sensor.
 42. The heat sealing device of claim 41,wherein the heat sealing element controller controls the amount ofcurrent applied to the heat sealing element in order to control thetemperature of the heat sealing element.
 43. The heat sealing device ofclaim 42, wherein the heat sealing element controller increases theamount of current when the temperature of the heat sealing element isless than a predetermined temperature.
 44. The heat sealing device ofclaim 43, wherein the heat sealing element controller decreases theamount of current when the temperature of the heat sealing element isgreater than a predetermined temperature.
 45. The heat sealing device ofclaim 44, wherein the heat sealing element controller maintains the heatsealing element temperature at a constant predetermined temperature. 46.A vacuum packaging appliance for use in evacuating vacuum packagingreceptacles, said vacuum packaging appliance comprising: a vacuum pump;a heat sealing element arranged to hermetically seal said vacuumpackaging receptacle; a temperature sensor providing data relating to atemperature of the heat sealing element; and a heat sealing elementcontroller operable to actuate said heat sealing element with a controlsignal, wherein the heat sealing element controller also directs exhaustof the vacuum pump under the heat sealing element when the temperatureof the heat sealing element has exceeded a predetermined temperature.47. The vacuum packaging appliance of claim 46, wherein the heat sealingelement controller sends a signal to open a valve when the temperatureexceeds a predetermined temperature.
 48. The vacuum packaging applianceof claim 47, wherein the exhaust of the vacuum pump is directed througha passage below the heat sealing element.
 49. The vacuum packagingappliance of claim 47, wherein the temperature of the heat sealingelement is maintained within a predetermined temperature range.
 50. Thevacuum packaging appliance of claim 47, wherein the heat sealing elementcontroller provides a signal to activate the heat sealing elements basedon one or more inputs.
 51. The vacuum packaging appliance of claim 50,wherein the inputs include heat sealing element temperature, amount ofliquid present in a trough, and operator selections of desired heatseals.
 52. A vacuum packaging appliance for use in evacuating andsealing a vacuum packaging receptacle, said vacuum packaging appliancecomprising: a vacuum pump for evacuating a vacuum packaging receptacle;heat sealing elements arranged to hermetically seal said vacuumpackaging receptacle; wherein the heat sealing elements comprise twowires; a temperature sensor providing data relating to a temperature ofthe heat sealing elements; and a heat sealing elements controlleroperable to actuate said heat sealing elements with a control signal,wherein the controller determines if one or both of the wires of theheat sealing elements are to be actuated based on a predeterminedcondition.
 53. The vacuum packaging appliance of claim 52, wherein theheat sealing element controller determines that only one wire is to beactuated when the predetermined condition is that a current temperatureexceeds a predetermined temperature.
 54. The vacuum packaging applianceof claim 52, wherein the heat sealing element controller determines thatboth wires are to be actuated when the predetermined condition is that acurrent temperature is below a predetermined temperature.
 55. The vacuumpackaging appliance of claim 52, wherein the predetermined condition isa user selected mode of operation.
 56. The vacuum packaging appliance ofclaim 52, wherein the heat sealing element controller determines thatboth wires are to be actuated when the predetermined condition is thatthe presence of liquid is detected.
 57. A method for controlling avacuum packaging appliance for use in evacuating and sealing a vacuumpackaging receptacle, comprising the acts of: evacuating a vacuumpackaging receptacle; providing two heat sealing element wires to sealthe vacuum packaging receptacle; providing a heat sealing elementcontroller operable to actuate said heat sealing element wires with acontrol signal, wherein the controller determines if one or both of thewires of the heat sealing elements are to be actuated based on apredetermined condition.
 58. A method for controlling a vacuum packagingappliance as in claim 57, wherein the heat sealing element controllerdetermines that only one wire is to be actuated when the predeterminedcondition is that a current temperature exceeds a predeterminedtemperature.
 59. A method for controlling a vacuum packaging applianceas in claim 57, wherein the heat sealing element controller determinesthat both wires are to be actuated when the predetermined condition isthat a current temperature is below a predetermined temperature.
 60. Amethod for controlling a vacuum packaging appliance as in claim 57,wherein the predetermined condition is a user selected mode ofoperation.
 61. A method for controlling a vacuum packaging appliance asin claim 57, wherein the predetermined condition is that the presence ofliquid is detected.
 62. A method for controlling a vacuum packagingappliance having an evacuation mechanism and a sealing mechanism, themethod comprising: preheat energizing a sealing mechanism in order topreheat bag material disposed within the vacuum packaging appliance; andseal energizing the sealing mechanism in order to seal the bag materialdisposed within the vacuum packaging appliance.
 63. A method as recitedin claim 62, wherein the preheat energizing step is performed inconjunction with an evacuation step.
 64. A method as recited in claim63, wherein the preheat energizing step brings the sealing mechanism toa lower temperature than the seal energizing step.
 65. A vacuumpackaging appliance for use in evacuating vacuum packaging receptacles,said vacuum packaging appliance comprising: a vacuum pump coupled with avacuum chamber, said vacuum chamber arranged to receive a vacuumpackaging receptacle; a heat sealing element arranged to hermeticallyseal said vacuum packaging receptacle, said heat sealing elementdisposed inside of said vacuum chamber; a temperature sensor providingdata relating to a temperature of the heat sealing element; and a heatsealing element controller operable to actuate said heat sealing elementwith a control signal, wherein the heat sealing element controller alsodirects exhaust of the vacuum pump under the heat sealing element whenthe temperature of the heat sealing element has exceeded a predeterminedtemperature.